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General Discussion To Gateway To Airguns => Airgun Gate => : Bhawanna July 17, 2008, 04:57:39 AM

: b26 tune kits
: Bhawanna July 17, 2008, 04:57:39 AM

i wanted to start playing with tuning guns and decided to start with a b26.  i went to macarri's site for the tune kit and he has discontinued it because of the difference in manufacturing tolerances.  if you can't get the stuff from macarri then where do you get the seals and springs?

: RE: b26 tune kits
: preez July 17, 2008, 05:28:21 AM

You can use small apex seal from Maccari. It fits fine.  I don't know about the spring though.

Chris

: Check the size of the seal in it.
: 3n00n July 17, 2008, 08:04:37 AM

ARH lists the OD of most seals. Since chinese tubes canvary by as much as 200 thousanths of an inch {.200"} for the same model, it is really quite difficult to use a single size seal tofit them all. . .(http://../images/emoticons/frown.gif)

: RE: b26 tune kits
: CharlieDaTuna July 17, 2008, 08:06:47 AM

The small Apex may or may not work just fine and JM wouldn't make that statement if it wasn't true. We, Jim and I, have discussed it at great length several times and it you think it not a problem, just ask TCup. It's starting to be a real crap shoot and it depends on where the tube was made and when. Jim is right. It has been a pain and beginning to be more so.

: thanx guys....
: Bhawanna July 17, 2008, 08:14:08 AM

i got 3 responses from the people who know and i have decided to scap the b26 idea!.........thanx guys.  seems like everytime i want to advance my airgun skills something screws it up!.....does anyone know where i can get a tune kit for daisy red-ryder?...maybe that is more my speed...ha!

: Don't give up!
: preez July 17, 2008, 01:58:56 PM

Use original parts, just be careful not to damage the seal. Your gun will still benefit from the tune.

Chris

: RE: thanx guys....
: TCups July 17, 2008, 02:41:51 PM

Yep, not one to throw cold water on a deal, but . . .

Sizing the seal can be done, and even if you end up buying 2 or 3 before you get it right, it's not like seals cost an arm and a leg.  However, don't plan on dropping an R9 spring and custom guide into a B26 with a narrow ID tube.  I tried that and failed.  The R9 custom tune kit spring guide has a metal bushing on the end opposite the piston that is too large OD to allow the spring to be compressed and put back in the gun.  Ooops.  OK, well, lets carefully size that down until it fits . . .  No joy.  Even though I could compress and re-assemble the B26 with the re-sized bushing, the problem was that, in compression, the OD of the spring expanded just enough to bind and grind inside of the piston.  When I reassembled and tried to cock the gun "crunch".  So, Crap!  Out comes the R9 spring and custom guide, now with an undersized rear bushing  on the guide that will be sloppy if I try to drop it in my Beeman R9.  I had to go to the lower power spring and the stock guide.  OK, but not what I originally had in mind.  So, I was 3 tries getting the right size seal and two tries at the right spring before I could get the gun back together, and then with a different spring and a loose stock spring guide  

Well, I said I wanted to have a learning experience with the BAM B26, and I got it!  It does shoot OK now, but I can entirely understand why Jim M can't offer a standard "kit" for the gun, then be expected to suffer the slings and arrows of dissatisfied customers when it doesn't fit.  Life is too short for that stuff.  And the good guys who make springs and do the custom tunes aren't getting rich doing it to begin with.

So, here's a suggestion:  if you're a rookie and you want to consider working on your own air gun, the first quality tool to buy is a set of digital calipers.  If you measure the exact size of the tube ID, factory seal OD, piston OD, spring OD and ID, and guide OD and accurately communicate the size info, you have a much better chance of getting it right parts the first time.  But when the manufacturers significantly change the size and tolerances of their airguns frequently, It's not reasonable expect the Jim Maccari's of the world to jump to change with them, or to refund your money on the used parts if you have an odd size gun and screw something up.

: .200???
: vinceb July 17, 2008, 02:45:48 PM

That's almost a quarter of an inch - are you sure you it's that much???

: 'With the narrow ID tube'...
: vinceb July 17, 2008, 02:47:36 PM

The 2 B26's I tried both had the same 25mm tube as my B20. Are you saying that some of them are now coming out with the long-promised 26mm tube?

: RE: b26 tune kits
: CharlieDaTuna July 18, 2008, 12:14:16 AM

Three cheers and a tip of the hat to TCup. And no, it's not the "promised" 26mm tube, just a variance in the tolerances in the tube sizes by different manufactures or even the same ones on different machines perhaps. We're talking differences of .030 or so  which can be a lot.

: That's a shame...
: vinceb July 18, 2008, 12:32:55 AM

The last couple of BAM guns I had apart (a Ruger AirHawk and a Quest 800X) seemed to show a downturn in manufacturing quality. I was hoping that these were flukes.

: That may be a conservative guess . . .
: 3n00n July 18, 2008, 03:05:02 AM

Unfortunately, I've had a few duplicatechinese rifles that parts from any of the others wouldn't evenfitother ones. The worst tube I think CdT ever saw, was one Itook over therethat had been 'coated' with something like JB Weld to cover variencein the compression tube from one end to the other. "Just nasty" was mentioned several times over that tube.

So far .2" is the maximum difference in tube thatI've seen in the same model, but I only tinkered with a few dozen chiclones before I gotburnt out on having to remachine nearly every moving surface, just to get one to function at all.Gave nearly all of them away, but I knew they wouldn't be used. Doc TCups now has firsthandexperiance in exactly why I quit buying the chiclones.

Really tough to fix one,when none of the parts fit the way thatthey're supposed to . . .